Natural-abundance carbon-13 nuclear magnetic resonance spectroscopy will be developed as a tool for structural studies of glycoproteins. Because of the highly resolved nature of the carbohydrate portions of 13C NMR spectra of glycopeptides and glycoproteins, and because of the ability of 13C NMR to examine native glycoproteins, this technique is an important new tool for glycoprotein research. The specific goals of this proposal are: (i) Isolation and purification of a large number of complex glycopeptides and the analysis of their 13C NMR spectra for the purpose of creating an extensive library of 13C chemical shifts of model compounds. (ii) Enzymatic degradation of the above glycopeptides in order to create simpler structures whose 13C NMR spectra will help to interpret the spectra of the larger compounds. (iii) Determinations of the structure and dynamics of the carbohydrate moieties of intact glycoproteins, as follows. Various methods will be used to diminish the microheterogeneity of intact glycoproteins prior to recording their 13C NMR spectra. Exoglycosidases will be used to generate "native" glycoprotens with progressively simpler carbohydrate side chains, and comparative studies will be made of their 13C NMR spectra. Plasma glycoproteins will be studied most extensively. Exploratory studies of some membrane glycoproteins will be made. Biologically relevant nonenzymatically generated glycoproteins will also be studied.